Mercury-tube switch.



T. B. FREAS.

MERCURY TUBE SWITCH. APPLICATION FILED JANA, 1912.

Patented NOV. 24;, 1914.

[nyef UJQALL THO A lurid-T TEV' COMPANY, SF NEW'ARK,

UJLAlo S "B. FREAS, OF NEW YORK N. Y. AQoIGEt'UR TO THE THERMO ELECTRIC INSTRU- 1 GDRPORATXON 0'? NEW? JERSEY.

IEIEECURYJEU filVP-ECH.

Application filed January l, 1912.

'1 '0 all ir/wm it may concern Be known that l, Tnonas l3. FREAS. a citizen of the United States, residing: at all York. in the county of New York and State of New York. have invented a certain new and useful improvement in Mercury-Tube Switches. 01" which the following is a specitication.

lily invention relates to mercury tube switches for for example, in connection with constant temperature baths of the general. type illustrated in my issued Patent Xuinher 999,710, Qanted August 1. 1011, and in my pending application, filed Decenr her 4-. 1911. Serial Zlumber 663,951.

My present invention is concerned more particularly with certain details oi construc tion. l or exau'iple, the method of mountingther-rmtact needle in the mercury. the construrtion ol' the mercury tube itself with its tiller duct, and certain other details which will he hereinafter more particularly described and claimed.

ln the form illustrated in the accompanying drawings: Figure 1 is a central vertical section of the mercury tuhe. Fig. :2 is a plan view taken on the line 1. 3 is a fragmentary section taken on the line Q2. Fig. Fig. is a section talren on the line l l, Fig. 2.

Similar numerals refer to similar parts th roughout thesei'eral views.

The hody oi the tube consists of a vertical portion 37 haying a horizontal foot or extension at its lower end if not shown}. the upper end of the hotly portion 2," is contracted in the ordinary ina r in an orifice '39 ahove which ll). The mercury is rendered alive by av conductor passing duet If? leading out the side hody. The needle which cons teru'iinal with which the conductor 4-9 i to he electrically connected by the rise 0: the me cury descends to or near the critic 39. It will be understood that in order to render the mercury tube very S'QIlSltlYQ cause the mercury to make and break connection with the needle upon ver slie l changes of temperature it is necessary that the needle point should come as precisely as possible into the middle of this orifice. In prior constructions it has been dilllcult. it not impossible, to accurately" adjust the needle and luring the point thereof at the Specification of Letters Patent.

Serial No. 668,34

p oper elevation and lateral position. Th

means .rhcrehv this is accomplished constitutos one of no novel characteristifoof my :oparatus The needle -53 ahore mentioned is mounted at the lower end of a rod L6 having a oat-1 l7 near its upper end, the ball being suinnuiuted by an extension 48 preferably oi in ulating material proi'iced with a handle The rod and ball are conductive, while the handle. l9 is insulated from them, hruuay itself be made of insulating material. Ball at? rests in a central depression formed in a cap 51 of conductive material which screws onto bushing 52 supported fry the insulating plate Bushing 52 cirr-umlerentially incloses the extension 40 of the mercury tube. and by preference a tight (llllllltlllOIl is made by the introduction of cement or other s 'table material 54 hetweeu them. Cap is insulated from surrounding oluccts by means of an outer cap It will he ohser ed that as a result of this construction the needle and its supporting rod are Inrotally supported from the ball. 1'' n l .1 a8

a cei'ltcr.

l permit needle may be swung lat of the orifice on hr reopen the .ecdle wnl he tirinly set. The needle may be elevated or lowered by sili-Trdilfi the cap 531 up or down in the stationary bu k Busl'iing is rendered electric ly alive by a screw 60 mounted in plate 53 and ha vine its inner end touching said bushing. as shown in section n 3 and in dotted lines in Fig. Said screw forms a binding; post in electric connection with the conductor 6]. shown in 2 and Conductors l? and Glare connected to the exterior conductors in any suitable manner, preferably as shown in 4, wherein the ends of the conductors l2 and connected to tubes 62 by passing up through plate 53 and connected with the conductors 5 i- 65 respectively; the connections being protected by housings 65's A "ller tube 4'0, best shown in Fig. 1, i supported in plate 53 and extends into the body 37 of the mercury tube and down to the foot 38. By this arrangement the mercury tube be readily filled "without the introduction of air bubbles which are freequentiy the source oiannoyance in devices of this class. Here the mercury is con veyed down into the foot Where it flows horizontally in such manner as to permit the escape of air as the mercury runs in.

Having thus described my invention, What l claim new and desire to secure by Letters' Patent is:

3.. ln combination, needle supported near tubeand having its point free to swing laterally within said tube, and oceans for adjusting the point of the needle laterally within the tube.

2. In combination, a mercury tube, a, cap end thereof, and a needle passing thro 1 an aperture in said cap and having 1 resting upon said cap whereby the needle pendant and free to be swung laterally, and means for clamping said ball in desired position against said cap.

3. In combination, a mercury tube, a metallic cap at the upper end of said tube,

61 ere electrically and 63 respectwely a mercury tube a the upper end of said nesses.

:umsooo a needle passing through an aperture in said cap, and having a ball resting upon said cap, and a bushing making screw connection with said cap for clamping said ball.

4:. ln combination, a mercury tube, a metallic sleeve at the upper end of said tube, a metallic cap screwing onto said sleeve whereby it is vertically adjustable, a needle in said mercury tube passing up through said 5 eeye and through an aperture in said cap, a ball supporting said needle and rest ing upon the apertured port-ion of said cap, an insulated cap fitting over said 111etallic cap, and an insulating bushing screwing into said insulating cup down onto said ball for-holding it and the needle set in proper position.

ln combination, a mercury tube a vertically adjustable centrally apertured cap at the upper end of said tube, a ball resting upon said cap at the central aperture therein, a needle suspended from saidbail, a handle extending upward from the ball, and an axially apertured bushing surroundin g said handle, and adapted to engage said ball for securing it in the position required,

In witness whereof, l have hereunto subscribed my name in the presence of two wit- THOEHS BL FREAR.

Witnesses ll'r'ra Gunmen, FRANK (I. Run. 

